What to plant in September in the Northeast and Midwest

Worked out for 67 cities from their own weather and frost dates, by zone.

What to sow and plant in September in the Northeast and Midwest, by zone: frost-free, highs above 82 °F (Wichita, Topeka and 3 more): garlic and flower bulbs; frost-free, highs of 72–82 °F (New York, Chicago and 56 more): broad bean and arugula; frost-free, highs of 61–72 °F (Portland, Maine, Montpelier and 2 more): garlic, broad bean, lettuce, broccoli, arugula and 1 more.

In the Northeast and Midwest, September is fall.

Frost-free, highs above 82 °F: Wichita, Topeka, Jefferson City, Dodge City and 1 more

In September, on average, these cities have highs of 82 to 85 °F and lows of 63 to 65 °F, 1.6 to 3.3 in of rain on 6 to 8 days; the day lasts 12 h 27 min to 12 h 29 min (on the 15th).

No frost in September in 10 years of data: frost-tender crops can go in too, if it is warm enough for them.

How	What	Where
plant cloves	Garlic	Wichita, Topeka and Dodge City
plant bulbs	Crocus, daffodil, hyacinth, tulip	Wichita, Topeka and Dodge City

Compared with August: new — garlic, crocus, daffodil, hyacinth and tulip; no longer sown — zucchini, green beans, sweet corn, corn and Napa cabbage.

Not starting in September: tomato (March, started indoors), bell pepper (March, started indoors), zucchini (April, started indoors), green beans (May, sown direct), lettuce (February, started indoors), peas (March, sown direct) and spinach (no month outdoors by these rules) — dates for Wichita.

Ready to harvest in September in Wichita, if sown in the right month: zucchini (July), green beans (July), watermelon (June), pumpkin (May), sweet corn (June), bok choy (July), borage (July) and corn (June).

Frost-free, highs of 72–82 °F: New York, Chicago, Boston, Philadelphia and 54 more

In September, on average, these cities have highs of 72 to 82 °F and lows of 53 to 66 °F, 1.2 to 5.0 in of rain on 5 to 12 days; the day lasts 12 h 28 min to 12 h 38 min (on the 15th).

No frost in September in 10 years of data: frost-tender crops can go in too, if it is warm enough for them.

How	What	Where
plant cloves	Garlic	Minneapolis, Omaha, Madison and 14 more
sow direct	Broad bean, arugula	New York, Chicago, Boston and 27 more
sow direct	Peas, cabbage, beet, mustard greens	New York, Cleveland, Atlantic City and 1 more
sow direct	Lettuce, broccoli	Boston, Detroit, Cleveland and 14 more
sow direct	Swiss Chard, kohlrabi	Cleveland and Erie
sow direct	Chickpea	New York, Boston, Philadelphia and 12 more
plant sets	Shallot	New York, Boston, Philadelphia and 12 more
sow direct	Kale	Cleveland
plant bulbs	Crocus, daffodil, hyacinth, tulip	Minneapolis, Omaha, Madison and 14 more

Compared with August: new — garlic, broccoli, crocus, daffodil, hyacinth and tulip; no longer sown — onion, cauliflower, zucchini, green beans, pumpkin, sweet corn, parsley, bok choy and 10 more.

Not starting in September: tomato (March, started indoors), bell pepper (March, started indoors), zucchini (April, started indoors), green beans (June, sown direct) and spinach (February, started indoors) — dates for Hartford.

Ready to harvest in September in Hartford, if sown in the right month: zucchini (July), green beans (July), watermelon (June), sweet corn (June), basil (July), bok choy (July), borage (July) and corn (June).

Frost-free, highs of 61–72 °F: Portland, Maine, Montpelier, Bangor and Duluth

In September, on average, these cities have highs of 70 to 71 °F and lows of 51 to 57 °F, 2.7 to 3.5 in of rain on 7 to 10 days; the day lasts 12 h 33 min to 12 h 37 min (on the 15th).

No frost in September in 10 years of data: frost-tender crops can go in too, if it is warm enough for them.

How	What	Where
plant cloves	Garlic	Montpelier and Duluth
sow direct	Broad bean, lettuce, broccoli, arugula	Portland, Maine and Bangor
sow direct	Radish	Duluth
plant bulbs	Crocus, daffodil, hyacinth, tulip	Montpelier and Duluth

Compared with August: new — garlic, radish, broccoli, crocus, daffodil, hyacinth and tulip; no longer sown — peas, onion, cabbage, beet, zucchini, green beans, sweet corn, parsley and 5 more.

Not starting in September: tomato (April, started indoors), bell pepper (April, started indoors), zucchini (May, started indoors), green beans (June, sown direct), peas (April, sown direct) and spinach (March, started indoors) — dates for Montpelier.

Ready to harvest in September in Montpelier, if sown in the right month: broad bean (June), peas (July), cabbage (May), beet (July), zucchini (July), green beans (July), sweet corn (June) and parsley (July).

How we work it out

For each city we use its average weather in September and the months after (highs, lows and rain for 2016–2025, ERA5 reanalysis via Open-Meteo) and its average frost dates. A crop starts in September if the month's mean temperature reaches the minimum soil temperature for germination on its card (we use the mean air temperature as a stand-in for the soil's) and if, over its first months (up to three), the average highs stay within its group's range, with no frost for crops that cannot take it. Crops started indoors count from the month they are planted out.

Temperature groups from Colorado State University Extension: cool-season crops prefer 60–80 °F and lose quality in heat; hardy ones grow in days as cool as 40 °F, semi-hardy ones from 40–50 °F (we use 50 °F); warm-season crops need days above 55 °F, and the most tender (tomato, pepper, eggplant, melon, watermelon, squash) above 60 °F, up to 95 °F. Crops the guide does not name go into the stricter group by their frost hardiness. Fava (broad) beans, which the guide does not name, count as hardy: hardy varieties are sown in fall and overwinter (RHS). Garlic and bulbs: a month before the first frost, and later only while the ground is not frozen (as on each city's page).

Cornell Cooperative Extension sets the season here: hardy crops from about four weeks before the last frost, warm ones after it, heat lovers about 18 days after; the last plantings from 3 weeks (radish) to 16 weeks (melons) before the first frost — counted from each city’s own frost dates.

This is a general rule from averages: your garden can be a week or two earlier or later, and a greenhouse or a cold frame brings the season forward. Greenly works out the dates for your location.

What to plant in September in the Northeast and Midwest

Frost-free, highs above 82 °F: Wichita, Topeka, Jefferson City, Dodge City and 1 more

Frost-free, highs of 72–82 °F: New York, Chicago, Boston, Philadelphia and 54 more

Frost-free, highs of 61–72 °F: Portland, Maine, Montpelier, Bangor and Duluth

How we work it out

Other months in the Northeast and Midwest